title: Carotid Wallstent placement difficulties encountered in carotid artery stenting.
abstract: OBJECTIVE
  The present study aimed to identify the types of curved lesions that are difficult to place Carotid Wallstent (CWS).
  
  
  METHODS
  The study targeted 31 consecutive carotid artery (CA) stenosis underwent carotid artery stenting using CWS. CWS placement success rate, stenosis location, lesion tortuosity, and relationship with stent placement failures were investigated. Lesion tortuosity was defined as the angle formed by 2 tangential lines between internal CA and common CA from the inflection point (IP) was defined as the center of lesion curvature. Stenosed lesions were classified into type A or B. Type A was defined as if the distal end of the stenosis was located proximal to the IP at a distance ≥0.5 of a vertebral body based on the posterior height of the 3rd vertebral body, otherwise was type B.
  
  
  RESULTS
  The stent placement success rate was 93.5% (29/31). The 2 unsuccessfully stented lesions, both lesions were significantly different from other lesions by having a lesion tortuosity less than 90° and by belonging to type B.
  
  
  CONCLUSIONS
  Since CWS placement is difficult in patients with CA stenosis located close to the IP at a lesion tortuosity ≤90°, open-cell stents should be considered as an alternative.
authors.affiliation: Department of Radiology and Interventional Neuroradiology, Ishinkai Yao General Hospital, 1-41 Numa, Yao, Osaka, 581-0036 Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Myouchin
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Takayama
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Taoka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Wada
authors.forename: Masahiko
authors.initials: M
authors.lastname: Sakamoto
authors.forename: Satoru
authors.initials: S
authors.lastname: Iwasaki
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kurokawa
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Kichikawa
keywords: Carotid Wallstent; Carotid artery stenting; Inflection point; Lesion tortuosity